Controllable synthesis of CdSe QDs@NPC composite improving electron–hole separation and enhancing visible-light photocatalytic activities toward RhB degradation

摘要

In this work, NPC (nanoporous carbon) is purposely employed to accommodate the semiconductor CdSe QDs (quantum dots) in the absence of any capping agent to facilitate the visible-light photocatalyst CdSe QDs@NPC composite. CdSe QDs@NPC composite has been achieved by the facile method of the incipient-wetness deposition, and furthermore characterised by powder X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller, transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The results of TEM and HRTEM show that CdSe QDs are implanted into NPC and bound to several nanometres. Both X-ray diffraction and HRTEM indicate that the as-synthesised CdSe QDs belong to the cubic phase. The photocatalytic performance of CdSe QDs@NPC composite has been evaluated by degrading the RhB under visible-light irradiation. NPC as electron acceptor and transport channel can enhance the synergism of CdSe and NPC by improving the electron-hole separation. Furthermore, the photocatalytic mechanism exhibits that h(+) and O-2(-center dot) species are the decisive, active species in the degradation process of RhB.